This application is submitted by the New York Colon Cancer Study Group (NYCCSG) investigators who have been exceptionally successful, individually and in collaboration, in studying genetic/molecular and dietary factors, and their interaction, in the development of intestinal cancer. This application brings powerful technologies at the Albert Einstein/Montefiore Cancer Center, the Strang Cancer Prevention Center at Rockefeller University, and the University of Nebraska School of Medicine, to the question of how a Western-style diet that mimics the major risk factors for colon cancer - high in fat and phosphate, low in calcium, vitamin D, choline, methionine, folate and fiber - interacts with genetic factors to increase probability of tumor formation in the intestinal tract. In project 1, novel mouse genetic models of intestinal cancer made at Einstein/Montefiore, including the Apc1636+/- mouse, the Muc2-/- mouse and a new mouse model with a point mutation that mimics a true human pathogenic allele, the Msh2G674S mouse, will be studied for modulation of cell maturation and tumor formation by the Western-style diet and the effects of partial reversal with calcium and vitamin D3. For the Apc1638 mouse, this will be extended to understanding the contribution of each component of the diet. Microarray analysis, utilizing a 27,000 member cDNA array, will establish a matrix of data, which defines the contributions of each dietary and each genetic component to the response, the underlying mechanisms, and how they interact on a molecular level. In Project 2, tissues from Project 1 will be utilized to specifically determine how the genetic and dietary factors, alone and in combination, recruit and modulate the b-catenin-Tcf -- c-myc/cyclinD1 -- cdk4/p21/p27 pathway, and Augenlicht, L related signaling and cell cycle machinery. Moreover, we will extend our analysis of the utilization, as well as mechanisms, of a block to c-myc transcription, which may be a key to how some nutritional factors can modulate tumor formation. This will make use of novel transcriptional imaging methods developed at Einstein and used by collaborating investigators in this Program. Project 3 extends the work of Projects 1 and 2 to human subjects, who will be maintained in the Rockefeller General Clinical Research Center (GCRC) and fed diets in which defined components (e.g., calcium and vitamin D3) are modulated. Biopsies taken during, and at completion of cross-over design studies will permit us to dissect how specific dietary components modulate intestinal cell maturation, biomarkers and profiles of gene expression, and how this relates to the alterations by similar dietary components in the mouse models, and to extensive gene expression data bases we have already developed that dissect cell maturation pathways in colonic cells. The four cores are Administration, Histopathology, Genomics, and Biostatistics. The Histopathology Core has extensive experience and standardized methodologies, and also incorporates laser capture microdissection, Real-Time PCR analysis, and tissue arrays. The Genomics Core capitalizes on the Einstein Microarray Facility, which is at the forefront of development and implementation of methods of gene expression profiling, and the extensive experience the facility, and members of this program have with such analyses. Moreover, this Core also includes sophisticated and novel methodology for analysis of locus specific and genome wide DNA methylation, transcriptional imaging of multiple genes simultaneously in situ, and high-throughput structural proteomics for determination of three dimensional structure of sequences with particularly interesting profiles of expression, but of currently unknown function. The Biostatistics Core at the North Shore University Hospital has already participated with members of this program on another National Cancer Institute (NCI) supported program that makes extensive use of microarray analysis of gene expression. Finally, a Pilot Project Program will provide new technologies to the Cores and new projects to supplement those proposed.